1. Field of the Invention
The present invention relates to a self-light-emitting device in which an EL element having a structure of an anode, a cathode and a light-emitting organic material (hereinafter referred to as an organic EL material) which generates EL (Electro Luminescence) and is sandwiched between them, is formed on an insulator, to an electronic instrument including the self-light-emitting device as a display portion (display or display monitor), to a thin film forming method of the organic EL material, and to a thin film forming device. Note that the self-light-emitting device is also called an OLED (Organic Light-Emitting Diodes).
2. Description of the Related Art
In recent years, a self-light-emitting device (EL display device) using an EL element, as a self-light-emitting element using an EL phenomenon of a self-light-emitting organic material, has been developed. Since the EL display device is a self-light-emitting type, a backlight as in a liquid crystal display device is not necessary, and further, since an angle of visibility is wide, it is considered to be hopeful as a display portion of an electronic instrument.
The EL display device has two kinds, that is, a passive type (simple matrix type) and an active type (active matrix type), and both have been earnestly developed. Especially, at present, attention is paid to an active matrix type EL display device. As an organic EL material which becomes an EL layer regarded as the center of an EL element, although a low molecular organic EL material and a high molecular (polymer) organic EL material are studied, attention is paid to the polymer organic EL material which is easier to handle than the low molecular organic EL material and has high heat resistance.
As a film growth method of the polymer organic EL material, an inkjet method proposed by Seiko Epson Corporation is considered to be promising. With respect to this technique, reference may be made to Japanese Patent Applications Laid-open No. Hei 10-12377, No. Hei 10-153967, No. Hei 11-54270, etc.
However, in the inkjet method, since the polymer organic EL material is jetted out, there can occur a problem of so-called flying deflection in which a droplet is coated on a portion except a necessary portion unless a distance between a coated surface and a nozzle of a head for inkjet is made suitable. The flying deflection is disclosed in detail in Japanese Patent Application Laid-open No. Hei 11-54270, and it is definitely disclosed that there can occur a deviation of 50 xcexcm or more from a target position to be coated.
The present invention has been made in view of the above problems, and has an object to provide means for forming a thin film by selectively coating an organic EL material made of polymer for every line or area, not by a spin coating method. Besides, the present invention provides a thin film forming device. Another object of the present invention is to provide a self-light-emitting device using such means and a method of fabricating the same. Still another object of the present invention is to provide an electronic instrument including such a self-light-emitting device as a display portion.
With respect to a coating liquid used for achieving the above objects, a solution is prepared by selecting a solvent with high solubility to an organic EL material. Note that, in the present specification, coating liquid for an EL layer in which the organic EL material is dissolved in the solvent is referred to as the coating liquid.
In the present invention, the coating liquid is contained in a coating liquid chamber, and when it is extracted by an electric field, its flying direction is controlled by an electric field generated by a voltage applied to a mask before it reaches a substrate, and a coating position can be controlled.